URP4161_PROJECT PLANNING:03

2.3 Work Breakdown Structure

Md. Sabbir Sharif Lecturer

Dept. of Urban & Regional Planning KUET, Khulna-9203, Bangladesh

What is the problem?

• Your boss: “How long will this take?” • You: “Between 1 and 6 months.” • People are not happy when you respond that way.

• You figure out that finishing anytime before six months will meet your promise.

• Your boss figures that with some hard work you can be done in a month!

• In reality, you don’t have the slightest clue how long it will take, because you don’t know the work to be done.

• Solution: Use divide and conquer • To give a good answer you have to break the work

down into activities for which you can get good timing estimates

• From these estimates you compute the estimated project duration

Activities to obtain good time estimates

• Identify the work that needs to be done • Work breakdown structure (WBS)

• Identify the dependency between work units • Dependency Graph

• Estimate the duration of the work to be done • Schedule

What are the activities that are needed to build a house?

• Surveying • Excavation • Request Permits • Buy Material • Lay foundation • Build Outside Wall • Install Exterior Plumbing • Install Exterior Electrical • Install Interior Plumbing • Install Interior Electrical

• Install Wallboard • Paint Interior • Install Interior Doors • Install Floor • Install Roof • Install Exterior Doors • Paint Exterior • Install Exterior Siding • Buy Pizza

1) Identify the work to be done: Work Breakdown Structure

2) Hierarchically organize the activities

• Preparing the building site consists of • Requesting permits • Surveying • Excavation • Buying of material • Laying of the foundation

• Building the house consists of • Prepare the building site • Building the Exterior • Building the Interior

3) Identify dependencies between tasks

• The work breakdown structure does not show any dependence among the activities/tasks

• Can we excavate before getting the permit? • How much time does the whole project need if I

know the individual times? • What can be done in parallel? • Are there any critical activities, that can slow

down the project significantly?

• Dependencies like these are shown in the dependency graph

• Nodes are activities • Lines represent temporal dependencies

START

Request

Survey ing

Excava tion

Buy Material

Founda tion

Build Outside

Wall

Install Exterior Plumbing

Install Interior Plumbing

Install Exterior Electrical

Install Interior

Electrical

Install Exterior

Siding

Install Wallboard

Paint Exterior

Install Roofing

Install Flooring

Paint Interior

Install Interior

Doors

Install Exterior

Doors

FINISH

The activity „Buy Material“ must Precede the activity

„Lay foundation“

Lay

Building a House (Dependency Graph)

4) Map tasks onto time • Estimate starting times and durations for each

of the activities in the dependency graph • Compute the longest path through the graph:

This is the estimated duration of your project

Building a House (Schedule, PERT Chart)

Duration

Start Time

Slack Time

Each Activity has a start time and an estimated duration

START

8/27/94

0 0

Request Permits

8/27/94

15 0

Survey ing

8/27/94

3 12

Excava tion

9/17/94

10 0

Legend

8/29/94

0

Buy Material

10/1/94

10 0

Lay Founda

tion

10/15/94

15 0

Build Outside

Wall

11/5/94

20 0

Install Exterior Plumbing

12/3/94

10 12

Install Interior Plumbing

12/3/94

12 0

Install Exterior Electrical

12/17/94

10 12

Install Interior

Electrical

12/21/94

15 0

Install Exterior

Siding

12/31/94

8 12

Install Wallboard

1/11/95

9 0

Paint Exterior

1/12/95

5 12

Install Roofing

1/19/95

9 12

Install Flooring

1/22/95

18 0

Paint Interior

1/22/95

11 0

Install Interior

Doors

2/8/95

7 0

Install Exterior

Doors

1/19/95

6 15

FINISH

2/16/95

0 0

0

Intranet WBS & Gantt Chart

Responsibility Matrix

The WBS represents a logical decomposition of the work to be performed and focuses on how the product, service, or result is naturally subdivided. It is an outline of what work is to be performed.

WBS – Rules of thumb A “Rule of thumb” is not a rule or a law. It is a strategy that we do because we know it works. o There is no rule as to the number of levels that a WBS has o Always start with Project Management as the first o Deliverable here should be no more than 10 top-level

Deliverables o Use a Noun: Object naming convention o Each sub-component must have a deliverable… the lowest

level of sub-division with a deliverable is called a “work package”

o Each and every sub-component must be assignable to one and only one person…

o Do not break the work into any inner detail than you intend to track or is of value – do not micro-manage